Synthesis of ribosomal proteins is coordinately regulated in yeast. We have recently isolated a number of genes which code for ribosomal proteins and have demonstrated that the coordinate regulation can occur, either at the level of transcription or translation, depending on cellular conditions. I plan to use these cloned genes to investigate the mechanism of coordinate control. Secondly, I wish to utilize these genes and their transcripts as models to study mRNA processing and gene duplication. Three approaches will be used. 1. I have isolated a putative regulatory mutant closely linked to tcm1, the gene for ribosomal protein L3. I plan to isolate more such mutants and determine their effect on coordinate regulation. 2. Most ribosomal protein genes are transcribed as large precursors which contain introns. There are a number of temperature sensitive mutants which prevent the processing of these mRNAs (rna2-rna11). I have isolated a suppressor which suppresses the ts phenotype of five of these rna mutations. I plan to investigate RNA processing by a biochemical and genetic analysis of the relationship between these procesing defective mutants and their suppressors. 3. Of nearly 20 ribosomal genes cloned, only two are closely linked; furthermore, these two linked genes are duplicated at one other site in the genome. I plan to sequence these two sets of linked genes and analyze their function by in vitro mutagenesis to gain some insight into the mechanism of gene duplication and the necessity for maintaining duplicate ribosomal protein genes in the genome.